What you´ve here is similar to my problem with the R class when I was the british player. In a modern war these ships can still be valuable units, however very limited by their low speed.
I was going to scrap the Rs and re-use the guns, either in new turrets or in the old ones rebuilt. That´s perhaps an option you could consider, if your resources are limited, for their replacements.
I don´t think they´re worth a minor refit or rebuilt, specially in Weswolrd, were many modern BBs are entering or have just entered service by now (early 30s). If you plan only to keep them in service until 1936, in my opinion, you should scrap or sell them.